How to Can CornRaw or Hot Pack

October 4, 2010

When it comes to preserving corn on the cob, the best way is to freeze it, which is a really simple process and results in much better summer flavor. But, if you don't have an extra freezer or room in the freezer(s) that you do have, you may want to can it using either the Raw Pack or Hot Pack method. There isn't much difference between the two methods. Some prefer that the corn is evenly heated through prior to canning, which some think is safer, but the flavor is pretty much the same. Corn is a low acid vegetable, which means that you should use a pressure canner in order to process it. Yes, pressure canners cost a bit more, but they last a lifetime and chances are that your grandchildren and their children will be using it one day. Our Presto® models double as both a water-bath canner and pressure canner, so you are getting two for the price of one. I have both, but only because I bought my water-bath canner first when I was uninformed and just a little ignorant of what my needs would be. I purchased a pressure canner the following year. There are times that I use both.

I like to gather all my materials in advance so that I'm not running around trying to find them. In fact, during canning season, I have a table that I keep all of my canning supplies on, all in one place, only putting them away when the season is over. To can corn you will need:

Fresh corn on the cobthe fresher the better. The ideal ears are ripe, but not bloated and the kernels can easily be punctured with your fingernail and will produce milky juice. If you can't can it as soon as you pick it or if you have bought it at the grocery store, you want to put it in the refrigerator or put it in a tub with ice on it. The sugars, which make for its sweet flavor, break down quickly at room temperature. It takes an average of 4.5 pounds of corn in the husks per each quart of processed corn. Bi-colored corn makes for really appetizing looking jars.

A sharp knife or a Corn Cutter, which makes removing the corn from the cob a real time saver. I definitely recommend this gadget. Your hands can get pretty sore using a knife to take the kernels off the cob.

A medium-to large-sized pot of boiling water.

Canning jars, lids (seals) and screw-bands. Your jars should appear new with no cracks or chips. Chipped rims can prevent proper sealing and cracked jars can break while processing. The jars should also be free of rust, as should the screw-bands. The lids should only be new or never used. If you have any doubt, buy new lids.

A large spoon, ladle or Pyrex measuring cup with which to put boiling water into the jars once filled with corn.

A large bowl or bags to put the corn in as you take it off the cob.

Indispensible canning gadgets like a jar lifter, jar funnel, lid lifter, or you can just buy a whole kit that has everything above, and also includes a jar wrench and jar cleaning brush.

A towel, jar rack or thick layer of newspapers on which to place the jars when they come out of the canner.

A soft vegetable brush for washing off the more stubborn corn silk.

Now that you have everything you need, you can start the fun part!

Get your jars and canner prepared. The jars and screw-bands should be washed with soap and water and rinsed well. Afterwards, you can use the sterilizer setting on your dishwasher and pull the jars out as you need them or you can fill them with water and put them in your canner, adding enough water to go about 1/2 way up the jars. Bring to a boil and then reduce the heat to simmer while you are prepping the corn. You should also put the seals (lids) in a saucepan with hot water and heat until the water is steaming, then reduce the heat to keep them hot. Don't boil the lids. I also like to alternate my lids facing up and down so they don't nest together which makes it much easier to grab one at a time.

Husk the corn, removing as much of the silk as possible. Then use the soft vegetable brush to remove the rest, but don't bruise the kernels while doing this. Remove the kernels from the cob. If you're using a knife, hold the cob at the small end and slide the knife down the ear. A sharp knife is critical, so you might want to consider having a good knife sharpener handy. You should be cutting about 2/3 to 3/4 of the depth of the kernels. (If making creamed corn, you cut about 1/2 the depth of the kernel and then scrape the cob with the back of the knife to remove the juice and the heart of the kernel.) The kernels will come off the cob in strips but readily fall apart while handling. You can put them in a bag or in a bowl, though a bowl is much easier to use. You might want to gently play with the kernels to get them to separate.

When ready you can pull your jars and start filling them with corn, using your jar funnel to make it quicker and cleaner, and then add hot water to the jars. (If you have previously heated the corn by covering it with water and heating until evenly hot, not boiling, then you can use the liquid from the corn, topping jars with hot water from the boiling pot to bring the liquid level up.) You should leave 3/4 to 1-inch headspace, which is the space between the corn and the top of the jar, to allow for expansion when processing. Jostle them back and forth a bit to allow air bubbles to escape, double-check the headspace, adding or removing liquid if necessary, use a clean, wet cloth to wipe the rims of the jars, put a lid on each and finger-tighten the screw-band snugly. Don't tighten forcefully or use a jar wrench.

The processing time will be 55 minutes for pints and 85 minutes for quarts but the pressure will differ with the altitude at which you live. Check the book that came with your canner, or you can go online and check the manufacturer's manual or research the correct pressure setting with your local university extension service.

Once you've reached the allotted processing time, turn the heat off under the canner and allow it to cool down gradually. You should NOT put it in cold water or move it to a cold, hard surface. Once the pressure gauge has reached zero or you have heard the safety release valves open, then you can remove the weight or open the valve. Wait another three minutes before opening the lid and make sure to tip the lid away from you in order to avoid a steam burn. Be careful of your hands and make sure you have someplace to safely set the lid.

Remove the jars using your jar lifter and place them on a thick layer of newspaper, a towel or a jar rack to cool. You may start to hear that unmistakable metallic pop as the jars seal, but it can sometimes take overnight for the jars to all seal. They should not be jostled during the cooling process.

To verify the seal, check the middle of the lids. If the lid is slightly concave and does not pop up and down when you push, then the seal is good. If it is not sealed, the middle of the lid will be slightly convex and will pop when touched. If this is the case, you can reprocess it, but you might want to consider making creamed corn at this point as it makes the texture a bit mushier. You can also put it in the fridge and use it within the next week or so. At this point you can remove the screw-band if you wish, label the jar with the contents and the date and place in a cool, dark, dry place.

I always get great pleasure out of hearing that pop when the lids seal. I don't care how often I can, it always makes me smile. I also tend to let my most recent canning project sit on the counter for awhile so that I can just admire the pretty jars.